Instability of stratified two-fluid flow in a Venturi flow meter

Abstract

In this dissertation the subject of stability of stratified two-fluid flows in an inclined channel is examined and modelled using classical fluid dynamics. The problem is motivated by the consideration of oil-water flows through a Venturi flow meter in the oil industry.

A background to both inviscid and viscous instability theories are given. An inviscid approach to the problem is undertaken and conditions for the onset of instability in the flow are derived. These conditions involve density contrast, Richardson number and critical slip velocity. Furthermore it is shown that a stable flow in an inclined channel may be made unstable by a small enough constriction.